This is the mail archive of the gcc-bugs@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[Bug tree-optimization/33294] New: [4.2/4.3 Regression] -fno-strict-aliasing -ftree-vrp miscompilation


Compile with "-O2 -fno-strict-aliasing", fails on amd64 and alpha at least. 
Doesn't fail with -fno-tree-vrp.  Seems to be related to bug 32575.  Breaks
linux kernel in many places (this asm is used with prefetch instruction).


struct T { void *p; } *t;

int main (void)
{
  struct T *a;

  a = t;
  asm volatile ("" : : "m" (*(unsigned long *) a));
  if (a)
    __builtin_abort ();
  return 0;
}


-- 
           Summary: [4.2/4.3 Regression] -fno-strict-aliasing -ftree-vrp
                    miscompilation
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: belyshev at depni dot sinp dot msu dot ru


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33294


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]